Comparison of the number of different phenotypically and functionally defined human hematopoietic cells detected in the tibias and femurs of mice 4 weeks after being transplanted with 10⁷ light-density human cord blood cells and then administered no further treatment (□) or FL, SF, and IL-6 injected daily at a low dose (▩), or three times per week for the 2 weeks before sacrifice at a high dose (▪). Values are the mean ± standard error of mean (SEM) of results obtained from three to seven individual mice in the three experiments described in Table 2.